Biopsychology

Question 1

What is localisation?

Answer 1

The theory that specific areas of the brain are associated with particular physical and psychological functions

Question 2

What is lateralisation?

Answer 2

The dominance of one hemisphere of the brain for particular physical and psychological functions.

Question 3

What are the four main lobes in the brain

Answer 3

Parietal lobe
Occipital lobe
Frontal lobe
Temporal lobe

Question 4

What does the motor cortex do and where is it?

Answer 4

BACK OF FRONTAL LOBE
Is responsible for the generation of voluntary motor movements.

Both hemispheres have a motor cortex, the right hem is responsible for the left side of the body’s movement and the left responsible for the right.

Different parts of the motor cortex exert control over different parts of the body. These are arranged logically.

Question 5

What does the somatosensory cortex do and where is it?

Answer 5

PARIETAL LOBE, CLOSE TO THE MOTOR AREA
Detects sensory events arising from different regions of the body. Using information from the skin, the somatosensory cortex produces sensations of touch, pressure, pain and temperature, which it then localises to specific body regions

The amount of somatosensory area devoted to a particular body part, denotes its sensitivity. Receptors for our hands and face occupy over half the area.

Both hemispheres

Question 6

What doe the visual centre do and where is it?

Answer 6

OCCIPITAL LOBE
Processing begins in the retina and then information is sent to the brain via the optic nerve. Most information then travels to the thalamus, which acts as a relay station, passing this information on the visual cortex.

Both hemispheres

The visual cortex contains different areas for colour, shape etc

Question 7

What does the auditory centre do and where is it?

Answer 7

TEMPORAL LOBE
Is concerned with hearing. The auditory pathway begins in the cochlea where sound waves are converted to nerve impulses which travel via the auditory nerve to the auditory cortex.

Cochlea-Brainstem (basic decoding e.g. duration and intensity)- Thalamus (relay station/further decoding) -auditory cortex (recognition of and response to sound).

Question 8

Outline Broca’s area

Answer 8

Named after french neuroscientist Paul Broca

“Tan” was a patient who could understand spoken language, but could not speak, nor express his thoughts in writing (broca’s or expressive aphasia)

Broca studies 8 other patients with similar language deficits. Post mortems revealed lesions to an area in the posterior portion of the frontal lobe of the left hemisphere. Patients with lesions on the right, did not have these language difficulties.

It was concluded that this area was essential for speech production.

Question 9

Outline Wernicke’s area

Answer 9

Named after Carl Wernicke- German neurologist. Located in the posterior portion of the left temporal lobe.

Patients with lesions in this area could speak, but not understand language. Wernicke proposed that language involves separate motor and sensory regions located in different cortical regions.
Motor-broca’s
Sensory-wernicke’s

Wernicke’s area is thought to be responsible for the recognition and processing of language.

Question 10

Evaluation of localisation

Answer 10

+ support for lang centres from aphasia studies
Expressive aphasia is an impaired ability to produce language.
Receptive aphasia is an impaired ability to understand language.

+wealth of evidence to support localisation from brain scans.
Peterson et al used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task.

+there is neurological evidence from cases of those who have had psychosurgery.
Walter Freeman developed lobotomy.
Neurosurgery is still used today in extreme cases of OCD and depression. Dougherty reported on 44 OCD patients who had undergone cingulotomy. Follow up at 32 weeks showed a third had met the criteria for successful response to surgery and 14% for partial response.
Findings show that over half of patients experienced no improvement, suggesting other factors may be involved and that localisation of function is an oversimplifying approach to the explanation and treatment of some behaviours.

-higher cognitive functions may not be localised
Lashley claimed that intact areas of the cortex could take over cognitive functions following injury to the area normally responsible for that function.

-communication may be a more important process to study than localisation.
Dejerine reported a case in which the ability to read was lost through damage to the connection between the visual cortex and Wernicke’s area.

-research into plasticity questions the argument of localisation.
Lashley described this as the law of equipotentiality, whereby brain circuits “chip in” so the same neurological action can be achieved. Although this doesn’t always happen, there are some well documented cases of stroke victims being able to recover those abilities that were seemingly lost through their illness.

Question 11

Outline Lashley

Answer 11

Investigated rats ability to learn a maze and found that the basic motor and sensory functions were localised, but that higher mental functions were not. He found the effects of deliberate damage to between 10% and 50% of the rats cortex was determined by the extent, rather than the location, of the damage.
The more cortex he removed, the more the rats ability to learn the maze was affected.

Question 12

Outline hemispheric lateralisation

Answer 12

Lateralisation : the dominance of one hemisphere of the brain for particular physical and psychological functions.

Left side of brain has language areas -Broca’s area and Wernicke’s area
Neural mechanisms for language are located primarily in the left half of the brain.

Research has also found that the right hemisphere excels at visual attention tasks and face recognition.

Therefore these functions are hemispherically lateralised.

The two hemispheres are connected via bundles of nerve fibres called the corpus callosum.

A way to investigate the different abilities of the two hemispheres is via the treatment for severe epilepsy includes cutting the corpus callosum- commisurotomy. This prevents violent electrical activity of a seizure from passing across the hemispheres.

Question 13

Outline split brain research

Answer 13

Procedure -Sperry devised a general procedure in which an image or word could be projected to a patient’s right visual field and the same, or different image could be projected on the left visual field.
In a ‘normal’ brain the corpus callosum would immediately share the information between both hemispheres giving a complete picture of the visual world. However, presenting the image to one hemisphere of a split brain patient meant that the information could not be conveyed from that hemisphere to the other.

Study type one- describing what you see ; When a picture of an object was shown to a patient’s right visual field, the patient could easily describe what was seen. If, however, the same object was shown to the left visual field, the patient could not describe what was seen and typically reported nothing was there. This indicates that the language centres are in the left hemisphere. The patients inability to describe what was in the left visual field was because of the lack of language centres in the right hemisphere.

Study type two- recognition by touch ;although patients could not attach verbal labels to objects projected in the left visual field, they were able to select a matching object from a grab- bag using their left hand. The left hand was also able to select an object that was closely associated with an object presented to the left visual field. In each case the patient was not able to verbally identify what they had seen but could ‘understand’ what the object was.

Study type three- composite words ;if two words were presented simultaneously, one on either side of the visual field (‘key’ to left and ‘ring’ to right) the patient would write with their left hand the word key and say the word ring.

Question 14

Evaluation of split brain research

Answer 14

High control- Sperry’s split brain research used scientific experiments with standardised procedures that were designed to test lateralisation in a highly controlled manner. This meant the findings would have been objective and valid.
Although there are issues with the conclusions drawn from Sperry’s research, it had contributed a greater understanding of brain processes and lateralisation i.e. that the left hemisphere is more geared towards verbal tasks and the right more visual.

Issues with generalisation- As fascinating as the findings from these studies are, many researchers have urged caution in their widespread acceptance, as split brain patients constitute such an unusual sample of people. There were only 11 who took part in Sperry’s research, all of whom had a history of epileptic seizures. It’s been argued that this may have caused unique changes in the brain that may have influenced findings.

Also some participants had experienced more disconnection of the hemisphere as part of their surgical procedure than others.

The control group Sperry used made up of 11 people with no history of epilepsy, may have been inappropriate.

Question 15

Evaluation of lateralisation

Answer 15

Lateralisation changes with age-lateralisation of function appears not to stay exactly the same throughout an individual’s lifetime, but changes with normal ageing. Across many types of tasks and many brain areas, lateralised patterns found in younger individuals tend to switch to bilateral patterns in healthy older adults.
SZAFLARSKI Found that language became more lateralised to the left with increasing age in children and adolescents, but after the age of 25, lateralisation decreased with each decade of life.

Differences in function may be overstated-One legacy of Sperry’s work is a growing body of pop psychological literature that overemphasises and oversimplifies functional distinction between left and right hemispheres. Although the ‘verbal’ and ‘non-verbal’ labels can be usefully applied to summarise the differences between the two hemispheres, modern neuroscientists would contend that the actual distinction is less clear cut. In the normal brain the two hemispheres are in constant communication when performing every day tasks, and many of the behaviours typically associated with one hemisphere can be effectively performed by the other one when the situation requires.

There are individual differences- brain function lateralisation is evident in the phenomena of right-or-left handedness, but a persons preferred hand is not a clear indication of the location of brain function. Although 95% of right-handed people have left-hemisphere dominance for language, 18.8% of left handed people have right hemisphere dominance for language function. Additionally, 19.8% of left handed people have bilateral language functions. Even within various language functions, degree and even hemisphere of dominance may differ.

Question 16

Outline brain plasticity

Answer 16

The brains ability to change and adapt as a result of experience. The brain would appear to be ‘plastic’ in the sense that it has the ability to change throughout life.

GOPNICK ET AL during infancy, the brain experiences a rapid growth in the number of synaptic connections it had, peaking at approx. 15,000 at age 2-3 years. This equates to about twice as many as there are in the adult brain. As we age, rarely used connections are deleted and frequently used connections are strengthened (synaptic pruning).

It was originally thought that such changes were restricted to the developing brain within childhood, and that the adult brain, having moved beyond a critical period, would remain fixed and static in terms of function and structure. Although the brains of young children exhibit more plasticity than older adults, recent research suggests that at any time in life, existing neural connections can change, or new neural connections can be formed, as a result of learning and experience.

Question 17

Outline functional recovery of the brain following trauma

Answer 17

Following physical injury or other forms of trauma such as the experience of a stroke, unaffected areas of the brain are often able to adapt and compensate for those areas that are damaged.

The functional recovery that may occur in the brain after trauma is another example of neural plasticity. Healthy brain areas may take over the functions of those areas that are damaged, destroyed or even missing.
Neuroscientists suggest that this process can occur quickly after trauma and then slow down after several weeks or months. At this point the individual may require rehabilitative therapy to further their recovery.

The brain is able to reword itself by forming new synaptic connections close to the area of the damage. DOIDGE Secondary neural pathways that would not typically be used to carry out certain functions are activated or “unmasked” to enable functioning to continue, often in the same way as before.
This process is supported by a number of structural changes in the brain including :

Axonal sprouting- the growth of new nerve endings which connect with other undamaged nerve cells for form new neuronal pathways.

Neuronal unmasking-WALL first identified what he called ‘dormant synapses’ in the brain. These are synaptic connections that exist anatomically but their function is blocked. Under normal conditions these synapses may be ineffective. However, increasing the rate of input to these synapses, as would happen when a surrounding brain area become damaged, can then open these dormant synapses. The unmasking of dormant synapses can open connections to regions of brain that are normally not activated, creating a lateral spread of activation which, in time, gives away to the development of new structures

Recruitment of homologous(similar) areas on the opposite side of the brain to perform specific tasks- an example would be if Broca’s area was damaged on the left side of the brain, the right-sided equivalent would carry out its functions. After a period of time, functionality may then shift back to the left side. LIEGEOIS found using fMRIs that for infants and young children with left hemisphere damage, language processing occurs primarily in the right hemisphere.

Question 18

Evidence for plasticity

Answer 18

KEMPERMAN investigated whether an enriched environment could alter the number of neurons in the brain. They found evidence of an increased number of new neurons in the brains of rats housed in complex environments compared with rats housed in laboratory cages. In particular, the rats housed in the complex environment showed an increase in neurons in the hippocampus, a part of the brain associated with the formation of new memories and the ability to navigate from one location to another.

MAGUIRE ET AL studied the brains of London taxi drivers and found significantly more volume of grey matter in the hippocampus than in a matched control group of novice drivers. This part of the brain is associated with most learning and in the development of spatial and navigational skills in humans and animals. As part of their training, London cabbies must take a complex test called ‘The Knowledge’ which assesses their recall of city streets and possible routes. It appears that the result of this learning experience is to alter the structure of the taxi drivers’ brains, who showed significantly more grey matter in the hippocampus. Also, the longer they had been in the job, the more pronounced the structural difference.

HYDE ET AL studied the effects of 15 months of instrumental music training in 6 year olds. There were significant increases in brain tissue in the motor and auditory areas. Those with the biggest changes showed the greatest improvements.

ZATTORE reviewed the research on the effects of musical training on the brain and found they were greater among children and young adults than older adults, suggesting plasticity reduces with age.

Question 19

Evidence for recovery from trauma

Answer 19

ELBERT concluded that the capacity for neural reorganisation is much greater in children than in adults, demonstrated by the extended practice adults require in order to produce changes.

BALLANTYNE ET AL found there is more plasticity for recovery after a stroke in infancy and childhood than in adulthood.

SCHNEIDER found that patients with the equivalent of a college education are seven times more likely than those who didn’t finish high school to be disability-free one year after a moderate to severe traumatic brain injury. They carried out a retrospective study based on data from the US Traumatic Brain Injury Systems Database. Of the 769 patients studied, 214 had achieved disability-free recovery after one year. Of these, 40% of patients with 16 or more years of education had achieved DFR, as had 30% of patients with 12-15 years of education. Just 10% of those with less than 12 years of education achieved DFR after one year. The researchers concluded that ‘cognitive reserve’ could be a factor in neural adaptation during recover from traumatic brain injury.

Question 20

Outline fMRIs

Answer 20

A technique for measuring changes in brain activity while a person performs a task.

It measures changes in blood flow in particular areas of the brain which indicates neural activity in those areas.

If an area of the brain becomes more active, there is an increased demand for glucose and oxygen.

The brain responds to this extra demand by increasing blood flow, which can be detected by the fMRI.

By giving participants specific tasks, researchers can see which areas of the brain are active as they have increased blood flow

Question 21

Strengths and weaknesses of fMRIs

Answer 21

+non-invasive ( does not expose individual to harmful radiation unlike CT SCANS and PET SCANS

+better temporal resolution ( shorted delay between activity and imaging) and spatial resolution depicting details by the mm rather than the cm, compared to PET SCANS

• measures changes in blood flow - not direct measure of neuronal activity in areas of brain.
• overlooks the networked nature of brain activity - focuses on localisation

Question 22

Outline Electroencephalogram

Answer 22

measures electrical activity in the brain via electrodes that are fixed to an individual’s scalp either individually or using a skull cap.

Recording represents brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity.

There are 4 distinct types of brain waves (alpha, delta, beta and theta) which are determined by their amplitude (size) and frequency (speed)

Often used by clinicians as a diagnostic tool because unusual patterns of activity may indicate neurological abnormalities such as epilepsy, tumours or disorders of sleep.

Question 23

Strengths and weaknesses of EEGs

Answer 23

+high temporal resolution unlike fMRI. Can accurately detect brain activity at a resolution of a single millisecond. This means that a researcher can accurately match a task or activity with the brain activity recorded.

+useful in the diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of activity in the brain that can easily be detected on screen

• the generalised nature of the information received. Signal is not useful for pinpointing the exact source of neural activity, and it does not allow researchers to distinguish between activities originating in different but adjacent locations.
• unlike fMRIs cannot tell us about activity in deeper parts of the brain.

Question 24

Outline Event-related potential

Answer 24

Are very small voltage changed in the brain that are triggered by specific events or stimuli.

They are difficult to pick out from all the other electrical activity being generated within the brain at a given time.

To find a specific response to a target stimulus requires many presentations of the same stimulus. These responses are then averaged together.

Any extraneous neural activity that is not related to the specific stimulus will not occur consistently, whereas activity linked to the stimulus will.

This has the effect of cancelling out the background neural ‘noise’, making the specific response to the stimulus in question stand out more clearly.

Two categories:
Waves occurring within the first 100 milliseconds after presentation of the stimulus are termed ‘sensory’ ERPs as they reflect an initial response to the physical characteristics of the stimulus.
ERPs after the first 100 milliseconds reflect the way in which the participant evaluates the stimulus. They are termed ‘cognitive’ ERPs as they demonstrate information processing.

Question 25

Strengths and weaknesses of ERPs

Answer 25

+can measure neural processes more accurately than using raw EEG data. They tell researchers how processing is affected by a specific experimental manipulation, for example, during presentation of different visual stimuli

+derived from EEG measurements, they have excellent temporal resolution which has led to their widespread use in the measurement of cognitive functions and deficits

• an issue is that, in order to establish pure data in ERP studies, background noise and extraneous material must be completely eliminated, this may not always be easy to achieve and a large number of trials are needed
• important electrical activities occurring deep in the brain are not recorded, meaning that the generation of ERPs tends to be restricted to the neocortex

Question 26

Outline post-mortem examinations

Answer 26

This is a technique involving the analysis of a persons brain following their death.

In psychological research, it is often used in those who have a rare disorder or particular difficulties in mental processes or behaviour during their lifetime.

Areas of damage within the brain are examined after death as a means of establishing the likely cause of the affliction the person suffered.

This may also involve comparison with a neurotypical brain in order to ascertain the extent of the difference.

Post-mortem evidence was vital in providing a foundation for early understanding of key processes in the brain.

Paul Broca and Karl Wernicke both relied on post-mortem studies in establishing links between language, brain and behaviour decades before brain scans became a possibility.

Question 27

Strengths and weaknesses of PMEs

Answer 27

+allow for a more detailed examination of neuroanatomical and neurochemical aspects of the brain than would be possible with the sole use of non-invasive techniques such as fMRI and EEGs.

+HARRISON claims that post-mortem studies have played a central part in our understanding of the origins of schizophrenia. He suggests that as a direct result of PMs, researchers have discovered structural abnormalities of the brain and found evidence of changes in neurotransmitters systems, both of which are associated with the disorder.

• causation is an issue. Observed damage to the brain may not be linked to particular behaviours
• limited because it is retrospective as person is already dead. Researcher is unable to follow up on anything that arises from the PME concerning a possible relationship between brain abnormalities and cognitive functioning.

Question 28

Define circadian rhythms

Answer 28

Changes in biological activity that show regular cyclical variation over 24hrs. Includes metabolic changes including temperature heart respiration and metabolism over this period, but the most studied circadian rhythm is the sleep-waking cycle.

Question 29

Define infradian rhythms

Answer 29

Changes in biological activity that show regular cyclical variation over a time period greater than 24 hours e.g. Women’s 28 day menstrual cycle

Question 30

Define ultradian rhythms

Answer 30

Changes in biological activity that show regular cyclical variation over a time period of less than 24hours e.g. The stages of sleep follow a pattern of cycles lasting about 90 minutes.

The difference between these rhythms is therefore the time period over which the rhythm occurs

Question 31

Define endogenous pacemakers

Answer 31

Internal body clocks that are created from within. They show periodicity and help to regulate and control other systems.

Question 32

Define exogenous zeitgebers

Answer 32

External cues from outside the body which also important in maintaining bodily rhythms. Light and dark is an important zeitgeber for both animals and plants.

Bodily rhythms show a similar daily pattern for people with different lifestyles. Much of the research focuses on the interaction between endogenous pacemakers and exogenous zeitgebers

Question 33

What is a circadian rhythm

Answer 33

Most humans (and animals) have a sleep wake pattern that repeats itself every 24 hours. We feel sleepy at night wake up in the morning.

Question 34

Outline Siffre

Answer 34

Spent 6 months inside a cave in Texas. There were no zeitgebers such as natural light or time. He had contact with the outside world via telephone but have no idea what time it was. His behaviour e.g. when he slept/woke and when he ate his meals was monitored. When he was awake, researchers put the lights on and when he went to bed, they turned the lights off.

His sleep/waking cycle was erratic at first but then settled into a fairly regular cycle of about 25 hours i.e. Slightly longer than the 24 hour day. When he emerged on the 179th day, it was only his 151st day